Why did Boeing sell the plane to the airline as an investment?

Boeing has two business units: Boeing Civil Aircraft Group (BCA) and Boeing Defense, Space and Security Group (BDS). These two businesses are supported by: Boeing Financial Company, which provides global financing services; * * Service Group, which provides various services for Boeing organizations all over the world; And Boeing Engineering, Operations and Technology Department, which is responsible for developing, acquiring, applying and protecting innovative technologies and processes. There will be many follow-up services from the moment the plane is sold, so it is an investment.